定时器技术选型の不同业务背景(一)

深藏阁楼爱情的钟 2022-07-13 04:21 161阅读 0赞

#  #

# 本文特色: #

网上关于定时器的文章很多,原本打算不写这篇博客了,可是后来想了一下,还是在巨人的肩膀上总结了一下自己的心得,本篇博客特色有2点:

1.结合具体的业务分析不同定时器的特点

2.结合业务讲解定时器技术选型的优先级.

# 业务背景: #

现在的公司是创业型的公司,同时也是创新型的公司,很多功能都不是很全面.于是就不得不一遍做业务一边丰富某些基本的功能.前几天做了一个定时器的功能.因为开始阶段需求不是很稳定,导致我不得不根据不同的需求需求不同的定时器的实现方式.正因为此,对各种定时器做了分析,下面根据不同的业务背景介绍一个各种定时器的技术选型.纯属个人之见,若有高见,请指教,感激不尽.

# 技术背景: #

公司的持久层环境是mybatis,框架用的是SpringBoot.框架层次用的是简单的三层:Controller/service/dao,面向接口的restful编程风格

# 不同背景下定时器选型: #

网上的定时器的文章很多,总结一下,主要的实现方式如下:

## 1.线程方式 ##

### 1.1线程方式Thread;利用线程的sleep ###

优点:在不了解定时器,的情况下可以简单的使用这个,

缺点: .只能开启一个定时任务,利用sleep的时间来控制任务开启的时间;

只能控制多长时间间隔之后开启任务,不能循环开启任务.

## 2.真正定时器 ##

### 2..1Timer方式; ###

优点:相比与Thread方式,这个定时任务可以控制开始结束时间,和延迟时间,和重复延迟时间,

缺点:Timer对于异常有无法预料的灾难性错误,因为timer只要有一个timertask报错,其他的任务都不能执行.是单线程的.但是用cocurrent版本的,使用线程池实现的.

解决方案:http://blog.csdn.net/lmj623565791/article/details/27109467

### 2.2.利用框架的方式: ###

#### 2.2.1.spring/springboot,这两个的实现方式是一样的,只不过springboot是spring的免配置的表现实现: ####

优点:可以使用简单的配置来使用,可以控制在某个时间刻,或者时间间隔执行,配置更灵活.主要有两种配置方式,时间率和表达式的方式,

缺点:不能动态的读取时间,所有的时间刻或者时间间隔必须是constant常量,如果要实现动态的配置则不能实现.这也是我的业务中不能选这个技术的原因.

附录:以下是常用的配置举例

**cronExpression表达式定义： **

<table style="table-layout:fixed; border-collapse:collapse; border:1px solid #ccc; width:360px"> 
 <tbody> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 字段</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 允许值</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 允许的特殊字符</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 秒</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 0-59</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * /</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 分</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 0-59</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * /</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 小时</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 0-23</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * /</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 日期</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 1-31</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * ? / L W C</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 月份</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 1-12 或者 JAN-DEC</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * /</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 星期</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 1-7 或者 SUN-SAT</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * ? / L C #</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 年（可选）</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 留空, 1970-2099</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> , - * /</td> 
  </tr> 
 </tbody> 
</table>

一些表达式的例子：

<table style="table-layout:fixed; border-collapse:collapse; border:1px solid #ccc; width:216px"> 
 <tbody> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 表达式</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 意义</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 0 12 * * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每天中午12点触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 ? * *"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每天上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 * * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每天上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 * * ? *"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每天上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 * * ? 2005"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 2005年的每天上午10:15 触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 * 14 * * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 在每天下午2点到下午2:59期间的每1分钟触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 0/5 14 * * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 在每天下午2点到下午2:55期间的每5分钟触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 0/5 14,18 * * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 在每天下午2点到2:55期间和下午6点到6:55期间的每 5分钟触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 0-5 14 * * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 在每天下午2点到下午2:05期间的每1分钟触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 10,44 14 ? 3 WED"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每年三月的星期三的下午2:10和2:44触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 ? * MON-FRI"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 周一至周五的上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 15 * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每月15日上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 L * ?"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每月最后一日的上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 ? * 6L"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每月的最后一个星期五上午10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 ? * 6L 2002-2005"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 2002年至2005年的每月的最后一个星期五上午 10:15触发</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> "0 15 10 ? * 6#3"</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 每月的第三个星期五上午10:15触发</td> 
  </tr> 
 </tbody> 
</table>

0 6 \* \* \*  每天早上6点

0 \*/2 \* \* \*  每两个小时

0 23-7/2，8 \* \* \*  晚上11点到早上8点之间每两个小时，早上八点

0 11 4 \* 1-3  每个月的4号和每个礼拜的礼拜一到礼拜三的早上11点

0 4 1 1 \*      1月1日早上4点

<table style="table-layout:fixed; border-collapse:collapse; border:1px solid #ccc; width:216px"> 
 <tbody> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 特殊字符</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-weight:bold; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 意义</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> *</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 表示所有值；</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> ?</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 表示未说明的值，即不关心它为何值；'?'也代表 '任何值', 但只用于“日期”和“星期几”，当其中一个设置了条件时，另外一个就要用'?' 来表示 '任何值'；</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> -</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 表示一个指定的范围；</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> ,</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 表示附加一个可能值；</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> /</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 符号前表示开始时间，符号后表示每次递增的值；</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> L("last")</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> ("last") "L" 用在day-of-month字段意思是 "这个月最后一天"；用在 day-of-week字段, 它简单意思是 "7" or "SAT"。如果在day-of-week字段里和数字联合使用，它的意思就是 "这个月的最后一个星期几" – 例如： "6L" means "这个月的最后一个星期五". 当我们用“L”时，不指明一个列表值或者范围是很重要的，不然的话，我们会得到一些意想不到的结果。</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> W("weekday")</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 只能用在day-of-month字段。用来描叙最接近指定 天的工作日（周一到周五）。例如：在day-of-month字段用“15W”指“最接近这个月第15天的工作日”，即如果这个月第15天是周六，那么触 发器将会在这个月第14天即周五触发；如果这个月第15天是周日，那么触发器将会在这个月第16 天即周一触发；如果这个月第15天是周二，那么就在触发器这天触发。注意一点：这个用法只会在当前月计算值，不会越过当前月。“W”字符仅能在day- of-month指明一天，不能是一个范围或列表。也可以用“LW”来指定这个月的最后一个工作日。</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> #</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 只能用在day-of-week字段。用来指定这个月的第几 个周几。例：在day-of-week字段用"6#3"指这个月第3个周五（6指周五，3指第3个）。如果指定的日期不存在，触发器就不会触发。</td> 
  </tr> 
  <tr> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> C</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> &nbsp;</td> 
   <td style="word-wrap:break-word; width:72px; height:32px; font-family:Arial; font-size:14px; vertical-align:middle; color:rgb(51,51,51)"> 指和calendar联系后计算过的值。例：在day- of-month 字段用“5C”指在这个月第5天或之后包括calendar的第一天；在day-of-week字段用“1C”指在这周日或之后包括calendar的第 一天。</td> 
  </tr> 
 </tbody> 
</table>

#### 2.2.2.spring/springboot+quartz方式: ####

优点:这种方式可以解决只用spring/springboot不能动态配置的缺点,可以利用参数的形式直接控制在某个动态的(从前端或者数据库读取的)时间间隔

缺点:技术上更重了,不得不配置quartz.以下是在gitup上的参考demo:      https://github.com/snailxr/quartz-spring\_demo

### 2.2.3.SpringTask方式: ###

优点:相比与quartz方式,更轻量级的spring自己封装的一套可以解决动态配置的一种定时器.

缺点:目前国内的相关资料不太多.

[下一篇博客][Link 1]是介绍我们公司的技术选型的过程,很有趣,可以瞅一眼^\_^

[Link 1]: http://blog.csdn.net/u010892841/article/details/53861581